chapter 23, 24 notes Flashcards
preoperative fluid balance
adh released during surgery curtails the ability of the kidneys to remove excess fluid
patients are replaced during surgery to compensate for surgical losses as well as hourly fluid requirements
third spacing- lack of fluid in the extracellular space- going to a third space.
crystalloids
cross rapidly from the vascular to the interstitial spaces (gut, lungs, dependent parts)
ONLY 1/3 REMAIN INTRAVASCULAR
Balanced salt solutions
LR, plasma-lyte, normosol
lactate is metabolized to generate bicarbonate
fluids to be used with blood
saline or plasma lyte
normal saline
dose dependent- hyperchloremic metabolic acidosis, and need for renal replacement therapy
hypertonic saline
used to control intracranial hypertension or rapid intravascular resuscitation
5% dextrose
similar to free water as dextrose is metabolized- not commonly seen in the or as hyperglycemia is associated with poor outcomes and the stress of the operative period causes blood sugar levels to increase
albumin
5%-25% solution compromised of 50% plasma proteins it remains in the intravascular space longer than crystalloids.
dextran 40&70
reduce factor VIII-Ag von willebrand factor. and hence platelet function.
potent osmotic agent used to treat hypovolemia. degraded to glucose increased bleeding times and noncardiogenic pulmonary edema.
hydroxyethyl starch
interferes with von willebrand factor VIII and platelet function. most common complication is pruritus. black box- do not use in ICU or sepsis
crystalloids versus colloids
SAFE (surviving sepsis campaign) stated crystalloids initially albumin when patient requires substantial amounts of crystalloids- yet one study stated mortality was higher with albumin.
young women with short gynelocigcal surgery
20-30ml/kg associated with less nausea and vomiting and improved pain control
maintenance fluid formula
first 10kg- 4ml/kg
second 10 gets 2ml/kg
each kg after gets 1ml/kg
three theories of fluid need
surface area can estimate water expenditure
calorie need depend on age, weight, activity, and food
urinary output and insensible losses correspond to age
d5 1/2 normal saline
hypertonic 432